There are a variety of known techniques for measuring flow through a conduit by the measurement of up-field and down-field speeds of a propagating sound wave. However, these known methods are ineffective unless the up-field sound waves can be separated from the down-field sound waves.
More recently, slightly different approaches have been proposed to address the limitations of conventional flow measurement techniques to model sound waves within a conduit. One such approach is described in U.S. Pat. No. 7,725,270. According to this approach, it is assumed that the measured sound wave is a free (unbound) sound wave propagating in a linear fashion. Thus, this approach ignores the reality that sound waves are actually bound by the conduit and that the sound waves travel in three dimensions. By simplifying the modeling of the sound waves, only an approximate model of the flow of the sound waves can be produced.
Thus, there is a need in the pertinent art for a system and method that are capable of accurately measuring the velocity of fluid flow and the speed of sound within a conduit. Additionally, there is a need in the pertinent art for a system and method that are capable of accurately modeling the phases of sound waves propagating through a fluid within a conduit, while taking the presence of the conduit into account. Further, there is a need in the pertinent art for a system and method that are capable of accurately modeling the superposition of multiple sound waves as they propagate through a fluid within a conduit.